1. Field of the Invention
The present invention relates generally to a viscous fluid type heat generator with variable heat-generating performance. More particularly, the present invention relates to a variable heat-generating performance viscous fluid type heat generator having an overall size reduced for enabling the heat generator to be easily mounted on a preselected mounting area in the body of an automobile.
2. Description of the Related Art
Japanese Unexamined Utility Model Publication (Kokai) No. 3-98107 discloses an automobile heating apparatus in which a viscous fluid type heat generator is incorporated. The viscous fluid type heat generator described in Japanese Unexamined Utility Model Publication (Kokai) No. 3-98107 includes a pair of mutually opposing front and rear housings tightly secured together by appropriate tightening elements such as through bolts to define an inner heat generating chamber and a heat receiving chamber separated by a partition wall through which the heat is exchanged between the viscous fluid in the heat generating chamber and the water in the heat receiving chamber. The heat receiving chamber is therefore arranged to be located outside but in close relation with the heat generating chamber. The heat exchanging water is introduced into the heat receiving chamber through a water inlet port and delivered from the heat receiving chamber toward an external heating system, and the water is constantly circulated through the heat generator and the external heating system.
A drive shaft is rotatably supported in the front housing via an anti-friction bearing so as to support thereon a rotor element in such a manner that the rotor element is rotated with the drive shaft within the heat generating chamber. The rotor element has outer faces which are face-to-face with the wall faces of the heat generating chamber and form labyrinth grooves therebetween, and a viscous fluid, for example, silicone oil is supplied into the heat generating chamber so as to fill the labyrinth grooves between the rotor and the wall faces of the heating chamber.
The automobile heating apparatus is further provided with a heat generating controller including a pair of engaged upper and lower covers defining therein a chamber in which a diaphragm element is received to form a part of the chamber as a controlling chamber enclosed by the diaphragm and the upper cover. The heat generating controller is attached to the lowermost portion of the front and rear housings. The controlling chamber of the heat generating controller fluidly communicates with the heat generating chamber via a fluid conduit, and the heat generating chamber in turn communicates with the atmosphere via an appropriate air hole formed in a connecting portion of the front and rear housings. The diaphragm of the heat generating chamber functions to adjustably change an internal volume of the controlling chamber in response to a vacuum pressure in the manifold of an automobile engine and a spring force of a coil spring arranged in a portion of the chamber of the heat generating chamber opposite to the controlling chamber.
When the viscous fluid type heat generator is incorporated in the heating system of an automobile, the heat generator per se is accommodated in a mounting space extending around an engine crank shaft so as to be operatively connected to the automobile engine. Therefore, the drive shaft of the viscous fluid type heat generator is rotated to rotate the rotor element within the heat generating chamber while applying a shearing action to the viscous fluid in the heating chamber. Thus, the viscous fluid generates heat when being sheared, and heat exchanging is conducted between the viscous liquid within the heat generating chamber and the water flowing through the heat receiving chamber. The heated water is circulated through the heating system of the automobile so as to warm the compartment within the automobile.
In the above-described conventional variable heat-generating performance viscous fluid type heat generator of Japanese Unexamined Utility Model Publication (Kokai) No. 3-98107, controlling of heat generation is conducted by a method described below.
Namely, when heat supply to the compartment of the automobile is excessive, the diaphragm of the heat generating controller is moved within the chamber of the upper and lower covers by the vacuum pressure of the engine manifold to increase the internal volume of the controlling chamber. Accordingly, the viscous fluid in the heat generating chamber is received by the controlling chamber of the heat generating controller. Therefore, heat generation within the heat generating chamber of the viscous fluid type heat generator is reduced due to reduction in the amount of the viscous fluid held between the inner wall of the heat generating chamber and the surface of the rotor element. As a result, supply of heat to the compartment within the automobile is reduced to lower a temperature in the compartment.
On the contrary, when the heat supply is excessively small, the diaphragm of the heat generating controller is moved within the chamber of the upper and lower covers to reduce the volume of the controlling chamber by the action of the spring force of the coil spring and an adjusting pressure supplied from a pressure adjusting hole formed in a part of the lower cover of the heat generating controller. Accordingly, the viscous fluid flows from the controlling chamber into the heat generating chamber of the viscous fluid type heat generator. Therefore, an increase in the amount of the viscous fluid held between the inner wall of the heat generating chamber and the surface of the rotor element of the heat generator is achieved so as to increase heat generation within the heat generating chamber. As a result, heat supply from the viscous fluid type heat generator to the compartment of the automobile is increased permitting the temperature within the compartment to go up.
Nevertheless, in the above-described variable heat-generating performance viscous fluid type heat generator, a separate heat-generating performance controller having a fluid receivable controlling chamber communicating with the heating chamber of the viscous fluid type heat generator must be arranged outside the heat generator to adjustably change the amount of viscous fluid held within the heat generating chamber of the heat generator to thereby control the heat-generating performance of the viscous type heat generator. Accordingly, an entire assembly of the viscous fluid type heat generator and the heat-generating performance controller becomes inevitably large in size resulting in making it difficult to mount the assembly in the body of the automobile.